The present invention relates to a machine for cutting pavement such as a sidewalk, a side edge of a bridge, a curb of a highway or the like. This machine is an improvement of the machine disclosed in Canadian patent no. 1,253,420 granted on May 2, 1989, and its U.S. counterpart U.S. Pat. No. 4,792,190 granted on Dec. 20, 1988.
The machine disclosed and claimed in the above Canadian and US patents is designed for cutting curbstones, sidewalks or the like. The machine comprises a cutting apparatus having two booms and a main rail along which a saw is moving. The main rail is mounted perpendicularly to the booms which are able to pivot downwardly and upwardly in unison. Each boom has a ground-contacting leg at its end for supporting the weight of the cutting apparatus and stabilizing it. When the cutting apparatus is put down on a surface that is not flat, adjustment of the height of the legs has to be performed simultaneously by at least two workers. Coordination work is thus necessary to install the cutting apparatus of the machine when the surface on which the apparatus is installed, is not flat. In such a case, failure to adjust the height of the legs may cause torsion at the attachment of the main rail on the booms and therefor possibly generating failures at the attachment.
Moreover, the machine disclosed in the above patent is not adapted to cut a surface that follows an inclined line on a long distance.
There is a need for a machine that overcomes these drawbacks.
The object of the present invention is to provide a machine for cutting pavement, which comprises a cutting apparatus that can be easily installed on a surface that is not flat.
More particularly, the object of the present invention is to provide a machine including a powered truck-like vehicle having a support base and an apparatus mounted on the base for cutting pavement. The apparatus comprises:
two spaced-apart cylindrical booms, each boom having one end pivotally mounted on the base and an opposite end;
tilting means mounted on the base for tilting each boom about its one end in a vertical plane;
a supporting bar mounted on the opposite ends of the cylindrical booms so as to be free to rotate about the cylindrical booms within a plane perpendicular to the cylindrical booms;
an extendible, ground-contacting leg at each end of the supporting bar for stabilizing the apparatus;
a rail-structure-holding head slidably mounted on each cylindrical boom so as to slide along the cylindrical boom and to be free to rotate about the cylindrical boom within a plane perpendicular to the cylindrical boom;
sliding means for sliding each head separately along the corresponding boom;
an elongated main rail;
main rail mounting means for mounting the main rail on the heads and for rotating the main rail about a longitudinal axis parallel to the elongated main rail;
a saw carrier mounted on the main rail;
displacing means for moving the saw carrier along the main rail in a first direction parallel to the longitudinal axis;
a motorized saw mounted on the saw carrier; and
moving means for moving the saw on the saw carrier in a second direction perpendicular to the longitudinal axis
As it can be appreciated, the machine according to the present invention has rail-structure-holding heads and a supporting bar that are mounted on cylindrical booms so as to be free to rotate about each of the cylindrical booms within a plane perpendicular to each of the cylindrical booms. Such free rotation of the supporting bar and the rail-structure-holding heads allows the apparatus to be put down on an uneven surface without necessitating simultaneous adjustment of the legs of the supporting bar. This free rotation also allows the main rail to adopt an inclined position along which the saw may be moved to cut at an angle if desired.
According to a preferred embodiment of the invention, each of the rail-structure-holding heads has separate connecting means for allowing connection of the main rail mounting means at different distances away from the vehicle. This preferred feature allows either extension of the apparatus in order to saw beyond the legs mounted on the supporting bar, or compact settlement of the apparatus in order to occupy one road line in addition to the road line occupied by the vehicle.
According to another preferred embodiment of the invention, the main rail mounting means comprises:
a helical rotary actuator attached to one of the rail-structure-holding heads, the helical rotary actuator having a shaft extending along the longitudinal axis about which the main rail rotates; and
at least one member attached to the shaft and to the main rail for driving the main rail into rotation about the longitudinal axis.
This preferred feature of the invention allows a wide rotation of the main rail about the longitudinal axis, that may reach 220xc2x0.
According to still another preferred embodiment of the invention, the saw carrier comprises at least one pole extending along the second direction perpendicular to the longitudinal axis; the saw is slidably mounted on said at least one pole; and the moving means for moving the saw on the saw carrier in the second direction comprise:
at least one motorized endless screw mounted on the saw carrier in parallel to the at least one pole and operatively engaging the saw,
a flexible dust cover covering the endless screw, and
a rod mounted on the saw carrier in parallel relationship above the endless screw, the rod preventing the dust cover from contacting the endless screw.
The dust cover according to this preferred embodiment of the invention prevents mud or the like to clog the endless screw, and the rod prevents the flexible dust cover from contacting the endless screw and getting worn out by the back and forth movement of the saw on the saw carrier along the second direction. Replacement of the dust cover is time consuming and therefore, involves expenses.
According to a further embodiment of the invention, the saw has a rotary blade, a motorized propeller shaft for propelling the rotary blade, a holding structure surrounding the propeller shaft, and a cooling system. The cooling system comprises:
a ring-shaped recess made into the holding structure, the ring-shaped recess surrounding the propeller shaft and being in contact with it;
a water inlet in the ring-shaped recess;
a water outlet in the ring-shaped recess, the water outlet having an exhaust directed towards a top surface of the rotary blade;
an L-shaped water duct made into the propeller shaft, the L-shaped water duct opening into the ring-shaped recess and exiting at a bottom of the propeller shaft so as to bring water to a bottom surface of the rotary blade.
The cooling system according this preferred feature of the invention allows water to reach both surfaces of the rotary blade.
According to still a further embodiment of the invention, the saw has a rotary blade and an articulated guard substantially covering half of the rotary blade, said guard being pivotally mounted on the saw so as to uncover any portion of the periphery of the rotary blade. In the prior art, the guard can only be mounted in two opposite positions on the rotary blade. This preferred embodiment of the invention allows the articulated guard to be secured at any position around the rotary blade and to free any desired side of the rotary blade for better convenience.
According to another further embodiment of the invention, the apparatus also comprises locking means for locking the saw carrier when the powered truck-like vehicle is moving so as to prevent any sliding motion of the saw carrier along the main rail. This locking means has the advantage of securing the saw carrier along the main rail and preventing its displacement when the vehicle is moving.
The invention, its operation and its advantage will be better understood upon reading the following non restrictive description of a preferred embodiment thereof, made with references to the accompanying drawings.